In many instances, it is desirable to introduce a substance into a live avian egg prior to hatch. Injections of various substances into avian eggs is commonly referred to as in ovo injection. Such injections have been employed to decrease post-hatch mortality rates, increase the potential growth rates or eventual size of the resulting bird, and even to influence the gender determination of the embryo. Similarly, injections of antigens into live eggs have been employed to incubate various substances used in vaccines which have human or animal medicinal or diagnostic applications. Examples of substances that have been used for, or proposed for, in ovo injection include vaccines, antibiotics and vitamins. In addition, removal of material from avian eggs has been employed for various purposes, such as testing and vaccine harvesting.
An egg injection apparatus (i.e., in ovo injection apparatus) may comprise a plurality of injection devices which operate simultaneously or sequentially to inject a plurality of eggs. The injection apparatus may comprise an injection head which comprises the injection devices, and wherein each injection device is in fluid communication with a source containing a treatment substance to be injected. The in ovo injection apparatus conventionally is designed to operate in conjunction with commercial egg carrier carriers or flats. Egg flats utilized in conjunction with an in ovo injection apparatus typically contain an array of pockets that are configured to support a respective plurality of avian eggs in a generally upright orientation. The egg flats may be typically transported through the in ovo injection apparatus via an automated conveyor system for registering the egg flat beneath the injection head for injection of the eggs carried by the egg flat. In ovo injection of substances (as well as in ovo extraction of materials) typically occurs by piercing an egg shell to form an opening (e.g., via a punch), extending an injection needle through the hole and into the interior of the egg (and in some cases into the avian embryo contained therein), and injecting treatment substance(s) through the needle and/or removing material therefrom.
In some instances, in ovo injection may be implemented selectively such that the treatment substance is not dispensed into dead, infertile, or missing eggs. In this regard, a candling device may be used to classify the eggs in the egg flat conveyed through the egg injection apparatus as viable or non-viable. In some instances, the classification information may be transmitted to an egg remover for removal of the non-viable eggs such that only viable eggs are conveyed to the injection devices, and then the classification information is transmitted to the injection devices such that the treatment substance is only dispensed at locations where eggs (viable) are present. In other instances, the classification information may be transmitted directly to the injection devices such that the viable eggs are injected with the treatment substance, while the non-viable eggs are not injected therewith. Either of these manners of using classification information is typically referred to as selective injection.
The treatment substances used in ovo may typically be either oil-based or aqueous-based substances. Delivery of aqueous-based substances is accomplished using low pressure (typically less than about 30 psi (206 KPa)) to inject the eggs, while delivery of oil-based substances requires use of high pressure (typically more than about 200 psi (1378 KPa)) due to the viscosity difference over aqueous-based substances. Selective injection of aqueous-based substances is accomplished using low pressure solenoid valves in fluid communication with each injection device such that dispensing of the treatment substance can be individually controlled for each injection device. However, selective injection of oil-based substances would require high pressure solenoid valves, which are expensive compared to low pressure solenoid valves, for each injection device to provide individual control thereof.
Accordingly, it would be desirable to provide a fluid delivery system for implementation on an in ovo injection apparatus capable of providing selective delivery of oil-based treatment substances, without the need for every injection device to be in communication with a high pressure solenoid for facilitating individual control thereof. Furthermore, it would be desirable to provide an associated method that would facilitate selective injection of an oil-based treatment substance at high pressure without the need for high pressure solenoid valves in communication with each injection device.